Card edge connectors normally comprise retaining devices oil their two sides for cassette electronic components which contacts to the edge of card edge connectors to retain on the corresponding electrical circuit boards. When cassette electronic components are inserted into card edge connectors, cassette electronic components are electrically connected to the corresponding electrical circuit boards. Retaining devices make cassette electronic components connect to the card edge connectors firmly, to prevent the signal break off by shaking, and cassette electronic components are ejected from card edge connectors easily through rotating retaining devices. The China Patent Application Number 01273845 disclosed one of the related present invention, as shown in the FIG. 2, the card edge connector including an insulation body 2, plurality of terminals 4 which is set up inside of the insulation body 2, a pair of eject structures 1 set up on the two sides of the insulation body, said eject structure 1 is used to retain or to eject the sub-board 3 in the card edge connector, the eject structure comprises a main body 10, a eject portion 11, a locking unit 12, a exerting unit 13, a pivot unit 14, an interfere unit 17. When the sub-board 3 is ejected, our hands press on the exerting unit 13 and the pivot unit 14 of the eject structure 14 will spin, then the locking unit 12 ejects from a slot 30 of the sub-board 3, at the same time, the eject portion 11 pushes the sub-board 3 from bottom to top, until the interfere unit 17 reaches the bottom of the insulation body 2, then the sub-board 3 is ejected from the slot 20 of the insulation body 2.
Although it is very convenient to eject the sub-board 3 by applying the hand manual system to the exerting unit 13, the more space will be taken if the sub-board 3 is ejected from the card edge connector by using the exerting unit 13, thus applying the hand manual system to the exerting unit 13 can only be successful when the space of the mother board is big enough. Furthermore to satisfy the market demand, electronic products (i.e. the laptop) are becoming thinner and lighter than those before, when the number of electronic products increases, the amount of the card edge connectors used on the mother board also increases, and the space of the mother board will decrease, when the space of the mother board is too small to enable the hand manual system to the exerting unit 13, said sub-board can not be ejected. Therefore it is necessary to design a new type of card edge connector in order to solve the problem describe above.